Aim: Life changes due to the sudden onset of acquired brain injury (ABI) are drastic personal and social changes that require adaptation and are also an important indicator of the quality of life of family caregivers. However, there are no instruments for evaluating life change adaptation among family caregivers of individuals with acquired brain injury. This study aimed to develop the Life Change Adaptation Scale (LCAS) for family caregivers of individuals with ABI and examine its reliability and validity.